Yamaha YZ250F

Thank you.
Unfortunately only with 12 and more teeth.

I have found one with 11 teeth on aliexpress now.
Decided to invest 9 Euros for 2 pieces including shipping to France- will report here what I got...

Well, if it is from aliexpress my guess is you will get no name Chinese sprockets that only grip half the splines and is very loose fitting.
The kind that eats up the splines on the shaft.

j bjork said:

Well, if it is from aliexpress my guess is you will get no name Chinese sprockets that only grip half the splines and is very loose fitting.
The kind that eats up the splines on the shaft.

Click to expand...

I am afraid you might be right.
If this will turn out to be true, I will have to look for another solution.

For the beginning, I just need a sprocket on which I can put the chain, in order to determine the motor position.

But until the whole thing will be really running, there will be time for searching better alternatives...

Not much action here
I had big plans, a long weekend and water cut parts.
But I got a mail from the cutter, saying it wouldn't get finished this week.

I found some old photos from when I tested the motor on my nucular 24fet:





It ran nice, and I was able to confirm a kv of about 55 from what I remember.
But that was pretty much it I think.

Finally some parts





Everything except the cover over the primary chain, but that wont be needed for a while.

Looking sweet!

This collection of parts looks impressive

Curious to see what you will make out of them.
Especially this fat round rod.
What for is this ?

Elektrosherpa said:

Especially this fat round rod.
What for is this ?

Click to expand...

This:



A cut trough drawing of how it will end up.



Almost finished, I will leave it to someone with a better lathe for the finishing touches of the surfaces where the bearings will be.

This is amazing.
Hardly ever saw a more sophisticated motor mount.
:thumb:

Are you using an off the shelf jackshaft or something custom made?

I want to use my original Honda sprockets for the jackshaft part of the primary reduction but could only find one company in the UK willing to do it and would cost £200 and take 4 weeks. The length of time feels a lot and at £200 that would be nearly 6% of the total cost on just a jackshaft.

Not sticking with the Honda sprockets to save money, they're really high quality but couldn't find a premade jackshaft for a 520 sprocket anyway.

I'm hoping that I can get a custom made shaft, but I havent got that far yet.
I will start designing it when I have got the other parts in the drive together.

Maybe you can use a shaft like this:



The 16/20/4 should fit a JTF 1554 or JTF 522 for 520 chain, or JTF 1263 for 428 chain.

@jbjork I got the same motor in the mail a few weeks ago and have been building my my Raptor 700 conversion with it! I am in the same predicament as you with the sprocket. I ended up scouring the JT sprockets website just like you did and came across I believe the same sprocket that you found. I had to look through hundreds of sprockets on their site before I found one. >.< But yes, it was a 420 sprocket, although the splines were the same dimensions.

I was (still am) looking for a 9 tooth sprockets though. To make things more difficult, finding a 9 tooth 520 sprockets was also a hard find, but I ended up finding one. So what I ended up doing was taking that 420 sprocket from JT and this 9t 520 sprocket here: https://www.trialstoreusa.com/front-sprocket-montesa/ I cut the center of the 520 sprocket out, and cut the outside of the 420 sprocket off, and welded them together! It was quite hard, as a 9t sprocket provides VERY LITTLE room to work with and very little room for error. I did this all using a basic home grinder and dremel. :lol: It is far from the best solution, but I've got everything running and tested, and it seems to be holding up for now. I can't say I recommend it, but it's better than nothing. Another downside though, is that the JT sprocket's width doesn't fully take up all of the room on the QSMotor shaft. So I'd be nice to get a sprocket with more width, so as to distribute more of the torque onto more area of the shaft.

If you figure out anything with a sprocket please let me know. I'm looking for a 9t or 10t one for a 520 chain. I am in talks with one of the guys here https://www.ampsprockets.com/ who make sprockets for QS Motors and the ME motors. He wasn't aware of this new QS motor and sounded interested in making sprockets to fit them as long as there is a demand. So it's probably worth you shooting them an email so they can see there is some interest in them.

As a side note, I got that motor working along with an APT 96800 controller pushing 800 phase amps. I'm going to post a build thread soon, but it is an absolute beast and I'd say it'd rip the original Raptor 700 motor up in a contest. To be honest, it's probably way overkill in a light weight dirt bike, seeing as it's overkill in a sport ATV already! >.<

Interesting :thumb:

I have ordered 10-13 tooth 428 sprockets from sprocket specialists, but I then got a reply saying they dont have the 10 or 11 tooth.
I will talk to "my" water cutter and see what he can do.

Do you know how thick the sprocket can be and fit on the shaft?
It is a little hard to measure on the splines, because they taper off gradually and I don't have any sprocket that fits.
I'm thinking, if the sprocket is 7mm, you just push it in as long as it will go. Then measure how much it is between the sprocket and locking ring groove. If it is 5mm, then a 12mm thick sprocket should fit.

Edit: I measured as good as I could, and 10mm seems to be about it as far as I can tell.

QS also said the motor was overkill for my bike

Ok so here are my measurements. I doubled checked, and I ordered that same JT sprocket that you posted. That JT sprockets is 7.3mm in width, but ideally the part that fits the shaft could be 10.8mm before the taper begins. If the sprocket incorporated the same taper as the shaft, the total shaft length after the c-ring slit would be 17mm. I used one of the digital measuring tools to try and get my measurements the best I could. Here is a diagram I made.



jbork, as for my hack job to fit that JT sprocket onto my shaft. I 3d printed a spacer that goes all the way to the end of the taper, so it places my sprocket on the outside. The spacer is 11mm. For the ring area, I fit two 13/16 c-rings in there, and it all made for a nice right fit. Hopefully my welded sprocket job stays fine though, and I don't mess the shaft up any since I'm not fully utilizing the entire length of it. I've been test riding it quite a bit though, and probably spent 3 hours riding around my property with quite a few hard pulls on the motor. Everything is fine so far, shaft and sprocket are good. If you are looking to do the same type of thing as me, I can send the 3D file for the spacer. It's just a simple cylinder.

I was planning to buy two sprockets of the same type, weld them together and then mill of most of one of the sprockets, that way I get a sprocket that is a bit thicker.

I just skipped it and went with one thin sprocket, when then spline is done I will just weld the sprocket to the shaft

Nice drawing, thanks :thumb:

I spoke to the cutter, and he should be able to cut sprockets with good fit.
I think I will go for thicker sprockets, and machine them to fit the chain afterwards.
Something like 10 or 12mm thick probably, then I will get a good grip on the splines.

I planed to finish the motor mount this weekend, but it dosent seem like I will.
Mostly because too much other stuff came up.
At least I got some stuff welded:



Not the prettiest welds, but I think they turned out alright anyway.
It took a lot of heat, and a few blown fuses to get there..





I thought the left side would be hardest to drill, but it was the opposite:



I could lay it on the chain cover, and get it strait.



I at least got this far

It's starting to look properly cool! :thumb: What are they made of, 6082? Are they relatively "easy" to tig weld and what is the filler material used?

Yes, 6082 T651.
I used 4043 rods, it seems to be recommended from what I found.
I only had 2mm rods, thicker wound probably been better.
It not so much drip on with those small rods on this thick stuff, more like a constant feed :wink:

I think it was relatively easy to weld, once I got enough heat..

Finished welding the frame for now:



There has been some finishing work like this:



Made a piece to go between the bearings and installed them:





On this side there will be a seal outside of the bearing, but I will wait with installing that.
It is starting to fit nicely, I can take off and mount the swing arm with the motor in place.

Come across this motor the other day seen the 8000w and chuckled thought 50kw more like now i seen your build threads and there you have it top work my friend thats gonna be an evil monster ill have a good read through when i got the time, super envious what a tank of a motor.

Also helped clear up the spline variation differences lucky i not ordered as i thought id need a 17mm and its gonna be the 20mm better really i can get them cheap and good quality local gutted i csnt use 219 chain with it though would have slotted nice on my kuberg sat sorry for itself.

j bjork said:

I made a little box for the battery:

It is about 5mm thick, that is about what a fiberglass box with 4 layers would be.

Guess what, it didnt fit:

The nice cooling plate between the modules had to go.
I didnt plan to have a water cooled pack anyway, but it would have nice to have the alu for some inertia.

So the alu plate had to go, and after cutting down the box it fits:

I would have liked some more play, but maybe I can grind a little here and there to get some clearance.

I got this bad boy today too :wink:

This is not where it will be mounted, it is just to show that it dosent really fit anywhere..

Click to expand...

Hi,mate!

Tell me please why did you choose Sevcon controller, not Votol for instance?

Nennko said:

Hi,mate!

Tell me please why did you choose Sevcon controller, not Votol for instance?

Click to expand...

I have written quite a lot about different controllers I have considered in the thread.

But why I didnt go with votol was basically because I didnt find any suitable.
There is a high voltage model of em200 that I considered to run 2 of.
But qs didnt want to sell them because they were not reliable.

Ianhill said:

Come across this motor the other day seen the 8000w and chuckled thought 50kw more like now i seen your build threads and there you have it top work my friend thats gonna be an evil monster ill have a good read through when i got the time, super envious what a tank of a motor.

Also helped clear up the spline variation differences lucky i not ordered as i thought id need a 17mm and its gonna be the 20mm better really i can get them cheap and good quality local gutted i csnt use 219 chain with it though would have slotted nice on my kuberg sat sorry for itself.

Click to expand...

It should be a monster for sure, I have my doubts about if I will even be able to use all the power.
There are only a few times I can use more power than the ktm can deliver, and this should about double the power

j bjork said:

Nennko said:

Hi,mate!

Tell me please why did you choose Sevcon controller, not Votol for instance?

Click to expand...

I have written quite a lot about different controllers I have considered in the thread.

But why I didnt go with votol was basically because I didnt find any suitable.
There is a high voltage model of em200 that I considered to run 2 of.
But qs didnt want to sell them because they were not reliable.

Click to expand...

Yes, I have already read all the posts in this topic. Also regarding the controller choosing issues=))

I am currently directly talking with Votol and they offered to buy a motor from QS, and send them to see which of their controllers match best. Ridiculous honestly. And currently, they consider testing with the EM-260 model...

A bit another point, how long was the production time of the motor in QS?
They told me after I asked to buy this motor to wait until the beginning of the next month, probably by then they will be able to start production.